JP2010210448A - Operation inspection system and operation inspection method of excessive flow rate blocking valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve test reliability by maintaining differential pressure generated at upstream and downstream sides of an excessive flow rate blocking valve over a long time. <P>SOLUTION: The operation inspection system of an excessive flow rate blocking valve performs an operation inspection of the excessive flow rate blocking valve provided in instrument piping at a downstream side of penetration attached to a reactor containment vessel. The operation inspection system includes a connection section connected to the instrument piping at the downstream side by the excessive flow rate blocking valve; and a circulation system and a circulation pump that are connected to the instrument piping via the connection section and circulate water, thus maintaining the differential pressure generated on the upstream and downstream sides of the excessive flow rate blocking valve over a long time and improving the reliability of testing. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an operation inspection system and an operation inspection method for an overflow prevention valve.

  In the instrumentation piping that penetrates the containment vessel, a manual valve and an overflow prevention valve are installed as isolation valves outside the containment vessel, and measuring instruments such as pressure gauges and differential pressure gauges are installed downstream of the isolation valves. . The number of installed overflow prevention valves differs depending on the plant output, but about 80 or more are installed on average, and the number of installed valves is enormous.

  This overflow prevention valve performs an operation test at every periodic inspection of a nuclear power plant from the viewpoint of importance. However, in order to operate the overflow prevention valve, there are conditions such as differential pressure and flow rate. Since this condition is satisfied during the reactor pressure vessel pressure test in the latter half of the periodic inspection, the operation test of the overflow check valve is performed during the test. In addition, since there are some valves that cannot perform an operation test because the pressure on the upstream side of the overflow prevention valve is low, disassembly and inspection are unavoidable.

  Valves that have malfunctioned during the overflow check valve operation test must be overhauled. In some cases, it is necessary to extend the periodic inspection period. Therefore, it is necessary to improve the operation test method for the overflow prevention valve.

  There is Patent Document 1 as a known example of an operation check system for an overflow prevention valve. In the technique of Patent Document 1, a dedicated test device is connected to the downstream side of the overflow prevention valve, and an operation test by evacuation is performed.

JP 2006-226947 A

  However, when an operation test is performed by evacuation as in Patent Document 1, it is difficult to maintain a differential pressure generated on the upstream side and the downstream side of the overflow prevention valve for a long time.

  Therefore, an object of the present invention is to maintain the differential pressure generated on the upstream side and the downstream side of the overflow prevention valve for a longer time and to improve the reliability of the test.

  The present invention is characterized by comprising a connection part connected to an instrumentation pipe downstream from the overflow prevention valve, a circulation system connected to the instrumentation pipe via the connection part, and a circulation pump for circulating water. .

  According to the present invention, the differential pressure generated on the upstream side and the downstream side of the overflow prevention valve can be maintained for a longer time, and the reliability of the test can be improved.

It is the schematic showing the overflow check valve operation inspection system of Example 1 with the whole composition of instrumentation piping. It is the schematic showing the instrumentation piping at the time of removing an exclusive test device in the overflow check valve operation inspection system of this example. An enlarged view of the dedicated test equipment is shown.

  The instrumentation piping on the downstream side of the penetration attached to the reactor containment vessel (in other words, outside the reactor containment vessel) is provided with a main valve and an overflow prevention valve as isolation valves, and a pressure gauge on the downstream side And instruments such as a differential pressure gauge are connected. The overflow prevention valve includes, for example, a valve body disposed in a valve chamber of the casing, a spring that applies an elastic biasing force in a direction in which the valve body is separated from the valve seat, and a valve body in a direction in which the valve body is in proximity to the valve seat. A magnetic body for applying a magnetic urging force, and the valve body is moved by a balance of the elastic urging force of the spring, the magnetic urging force of the magnetic body, and the pressure of the flowing water. When the pressure of the flowing water (in other words, the differential pressure across the overflow prevention valve for flowing water) becomes equal to or higher than a predetermined set pressure (for example, about several tens of kPa), the overflow prevention valve The instrumentation piping is cut off by sitting on the seat. As a result, for example, when a leakage accident occurs in an instrumentation pipe and an instrument, water from the piping in the reactor pressure vessel and the reactor containment vessel is prevented from flowing out.

  In addition, the amount of leakage during operation described above is strictly defined in the overflow prevention valve, and in particular, since the gap between the valve chamber wall of the casing and the valve body is very narrow, foreign matter or the like is caught in the gap. May cause malfunction. Therefore, an operation inspection is periodically performed to confirm whether or not the overflow prevention valve operates normally. In the operation check of the overflow prevention valve, it is necessary to sufficiently secure the above differential pressure, which is the operation condition of the overflow prevention valve.

  Examples of the present invention will be described below.

  FIG. 1 is a schematic diagram showing the overflow prevention valve operation inspection system of this embodiment together with the overall configuration of instrumentation piping. FIG. 2 is a schematic diagram showing instrumentation piping when the dedicated test apparatus is removed in the overflow prevention valve operation inspection system of the present embodiment. In the following, the filled valves shown in the figure represent the closed state, and the white valves represent the opened state.

  The overflow check valve operation inspection system 1 includes a penetration 104 attached to penetrate the reactor containment vessel 102 and the reactor containment shield 103, and an upstream side of the penetration 104 from the reactor pressure vessel 101 (FIG. 1). Instrumentation pipe 105 connected to the middle left), instrument 119 such as a pressure gauge and differential pressure gauge disposed in instrumentation rack 108, and instrumentation from the downstream side of penetration 104 (right side in FIG. 1) An instrument 119 in the rack 108 and an instrumentation pipe 150 connected to the drain header 117 are provided.

  The instrumentation pipe 150 includes a pipe line connected from the penetration 104 to the drain header 117, and a measurement pipe line branched from the pipe line and connected to the instrument 119. In the pipeline connected from the penetration 104 to the drain header 117, a main valve 106, an overflow prevention valve 107, a rack inlet valve 109, and blow valves 112 and 113 are provided in that order toward the downstream side.

  The measurement conduit is branched between the rack inlet valve 109 and the blow valve 112. A meter inlet valve 110 is provided in the measurement pipe line, and a meter test valve 111 for meter calibration is branched between the meter inlet valve 110 and the meter 19.

  A drain receiving port 116 is connected to one side (left side in FIG. 1) of the drain header 117 via a drain valve 114 and a drain pipe. A water filling device (not shown) is connected to the other side (right side in FIG. 1) of the drain header 117 via a water filling valve 115 and a water filling pipe 118.

  The overflow prevention valve 107 is known as this type. For example, when the pressure of flowing water (in other words, the difference between before and after flowing water) becomes a predetermined set pressure (for example, about several tens of kPa) or more. The pipe line of the instrumentation pipe 150 is cut off. Normally, as shown in FIG. 2, the main valve 106, the rack inlet valve 109, the instrument inlet valve 110, and the drain valve 114 are open, and the instrument test valve 111, blow valves 112, 113, and the water filling valve 115 are closed. is there.

  An inspection connection port 120 is provided between the branch portion of the measurement pipe provided in the pipe of the instrumentation pipe 150 and the blow valve 112 by a T-shaped joint or the like that is a branch tee 130. The dedicated test apparatus 122 is connected to the inspection connection port 120 via a connection pipe 121 (for example, a connection hose). Thus, the instrumentation pipe 150 and the dedicated test device 122 are connected via the connection portion of the branch tee 130. Further, when the dedicated test device 122 is not attached to the instrumentation pipe 150, a closing plug 160 (see FIG. 2) is attached to the inspection connection port 120 of the instrumentation pipe 150 in place of the connection pipe 121. This closing plug 160 prevents leakage.

  FIG. 3 shows an enlarged view of the dedicated test apparatus 122. The dedicated test device 122 includes an inlet pipe 137 that draws fluid flowing in from the connector part 136 and the connector part 136 connected to the connection pipe 121 into the circulation tank 129, a circulation pump 124 that draws fluid into the circulation tank 129, and internal water of the circulation tank 129. Is provided with a circulation pipe 133 for returning the air to the lead-in pipe 137. The lead-in pipe 137 includes a gate valve 123, a circulation pump 124, a pressure gauge 125, and a flow meter 126 in order from the connector portion 136. In addition, the circulation pipe 133 includes a flow meter 134 and a flow rate adjustment valve 135 in order from the circulation tank 129 side, and joins the drawing pipe 137 between the gate valve 123 of the drawing pipe 137 and the circulation pump 124. As described above, the dedicated test apparatus 122 forms a circulation system that circulates the circulating water in the circulation tank 129 through the circulation pipe 133 and the lead-in pipe 137.

  The dedicated test apparatus 122 includes a vent pipe 127 that supplies the circulating water to the circulation tank 129 and a drain pipe 131 that discharges the circulating water held by the circulation tank 129 to the building drain treatment system. The vent pipe 127 includes a vent valve 128 that adjusts the flow rate of the circulating water. In addition, the drain pipe 131 includes a drain valve 132 that opens when drain water is discharged.

  Next, a test execution method of the operation test system for the overflow prevention valve in the present embodiment will be described.

  As shown in FIG. 1, in order to prevent unnecessary pressure from being applied to the instrument 119 in the instrument rack 108, the instrument inlet valve 110 is fully closed and the instrument test valve 111 is fully opened. Next, the closing plug 160 is removed from the inspection connection port 120 installed in the branch tee 130 of the instrumentation pipe 150. Then, the connector part 136 of the dedicated test apparatus 122 and the inspection connection port 120 are connected by the connection pipe 121.

  After the dedicated test apparatus 122 is connected to the inspection connection port 120 via the connection pipe 121, the gate valve 123 and the drain valve 132 of the dedicated test apparatus 122 are fully closed. Then, the vent valve 128 is opened, and circulating water is put into the circulation tank 129 from the vent pipe 127. The amount of circulating water injected into the circulation tank 129 can be confirmed with a level meter 138. Next, after fully opening the flow regulating valve 135 installed in the circulation pipe 133, the circulation pump 124 is started, and the values of the pressure gauge 125 and the flow meter 126 installed on the outlet side of the circulation pump 124 are confirmed. After confirming the flow rate with the flow meter 126, the opening of the flow rate adjustment valve 135 is throttled to ensure the minimum flow rate of the circulation pump 124.

  After the circulation pump 124 shifts to stable operation, the gate valve 123 is fully opened. By fully opening the gate valve 123, a differential pressure is generated in the overflow prevention valve 107 via the instrumentation pipe 150 and the connection pipe 121. Then, after confirming the operation of the overflow prevention valve 107, the gate valve 123 is fully closed and the circulation pump 124 is stopped. Finally, the connection pipe 121 connected to the inspection connection port 120 is removed, and the closing plug 160 is attached. The circulating water held in the circulation tank 129 is discharged from the drain pipe 131 to the building drain treatment system by opening the drain valve 132.

  As described above, it is connected to the instrumentation pipe 150 through the connection portion, and includes the circulation system for circulating water and the circulation pump 124, so that the gate valve 123 of the dedicated test device 122 is opened and the operation test of the overflow prevention valve is performed. During the operation, it is possible to maintain the differential pressure generated on the upstream side and the downstream side of the overflow prevention valve 107 by driving the circulation pump 124. Therefore, the reliability of the test can be improved.

  Moreover, the instrumentation pipe | tube with which the overflow prevention valve was installed may have less water holding | maintenance upstream from an overflow prevention valve on the piping structure. If a long time test is performed and a large amount of fluid is moved inside the pipe, the test may not be possible. Therefore, in order to maximize the suction force of the circulation pump 124, the amount of circulating water is reduced to the minimum by the flow rate adjustment valve 135 installed in the circulation pipe 133, and the test is performed. Thus, by providing the flow rate adjusting valve for adjusting the flow rate flowing through the circulation system, the test can be performed regardless of the amount of retained water upstream of the overflow prevention valve.

  This diaphragm can be arbitrarily selected by setting in advance in a test.

DESCRIPTION OF SYMBOLS 101 Reactor pressure vessel 102 Reactor containment vessel 103 Reactor containment vessel shield 104 Penetration 105 Instrumentation piping 106 Main valve 107 Overflow prevention valve 108 Instrumentation rack 109 Rack inlet valve 110 Instrument inlet valve 111 Instrument test valve 112,113 Blow valve 114, 132 Drain valve 115 Drain valve 116 Drain receiving port 117 Drain header 118 Drain header 118 Meter 120 Inspection connection port 121 Connection piping 122 Dedicated test device 123 Gate valve 124 Circulation pump 125 Pressure gauge 126, 134 Flow meter 127 Vent Piping 128 Vent valve 129 Circulating tank 131 Drain piping 133 Circulating piping 135 Flow rate adjusting valve 137 Intake piping 138 Level meter

Claims (3)

In the operation check system of the overflow prevention valve that performs the operation inspection of the overflow prevention valve provided in the instrumentation piping downstream of the penetration attached to the reactor containment vessel,
A connection part connected to the instrumentation pipe downstream from the overflow prevention valve;
An overflow check valve operation inspection system comprising a circulation system and a circulation pump that are connected to the instrumentation pipe via the connection portion and circulate water. The operation check system for an overflow check valve according to claim 1,
An overflow check valve operation inspection system comprising a flow adjustment valve for adjusting a flow rate through the circulation system. In the operation check method of the overflow prevention valve that performs the operation inspection of the overflow prevention valve provided in the instrumentation piping downstream of the penetration attached to the reactor containment vessel,
Water is circulated by a dedicated test device equipped with a circulation system and a circulation pump via a connection portion provided in the instrumentation pipe on the downstream side of the overflow prevention valve to generate a differential pressure in the overflow prevention valve. An over-flow check valve operation inspection method characterized by the above.

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